*{
    margin: 0px;
    padding: 0px;
    box-sizing: border-box;
}
.box{
    width: 800px;
    height: 1000px;
    border: 1px solid red;
    display: grid;
    grid-auto-columns: 600px 200px;
    grid-auto-rows: 1fr 2fr 2fr 2fr 1fr;
}
.box_box{

    border: 1px solid blue;
}
.b1{
    grid-column: 1/3;
}
.b2{
    grid-column: 2/3;
    grid-row: 2/5;
}